I had the same question. But i bought mine before 9/29 with big apple buddy distributer ( not insight ).
not sure if that matters. Its my understanding that any hardware shipper before 9/29 will automatically unlock to developer pro and that it would be up to me to update the firmware.
Good to hear that I am not the only one who doesn't understand the features of the Developer Pro account. (beside credits for cloud services)
When I received the license key last week, I had to update to the latest firmware, and therefore the "kali.." demo was deleted. So that makes it even more confusing.